Upgrade from 11Intro to 11(Full) - TERRIBLE PLAYBACK!!!

[John Moran]

I'm at my wits end, and super pissed that I can't find a solution for this EXPENSIVE problem!

Macbook Pro (2015 Retina)
16GB
SSD
300GB available on drive
Mac OS Big Sur (and earlier versions before this, attempting a fix)

Had Reason11 Intro for 2 years, worked great. Upgraded to Full Reason 11 this week - and since that moment have terrible playback issues. Even 1 simple track of a bass drum can't run without breaking up, crackling like crazy.

Tried all possible buffer settings.
Tried all possible preference settings
Opened Reason 11 in Low Resolution
...nothing helps.

And then to read Reason Studios acknowledge "This is a known issue, we're working on it."
Work on giving my my money back and downgrading me back to Intro, if that's what it takes.